Thorax cover Brown thorax cover (fine stretch film)
Legs Natural partridge (partridge)
Head Rusty (thread)
How to tie it
Lay a yellow thread underbody to the bend, with a translucent catgut body the underbody colour is what you actually see once the fly is wet.
Tie in cream ostrich barbs along the abdomen for gills.
Wrap natural catgut forward over the underbody to the 65% mark. Catgut goes translucent and slightly swollen when wet, which is exactly the look of a live mayfly nymph abdomen.
Tie in the fine brown stretch film for the thorax cover.
Dub a spiky thorax, then set partridge barbs as legs.
Pull the stretch film over the thorax, tie down, and finish the head with rusty thread.